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Bioenergy-butanol. Agenda. Bioethanol versus biodiesel Butanol (CH 3 CH 2 CH 2 CH 2 OH) Chemical properties How to make it?. Bioethanol versus biodiesel. Feedstocks (competition with food industry) Major producers Process Yields Production facilities. Butanol. Feedstock.
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Agenda • Bioethanol versus biodiesel • Butanol (CH3CH2CH2CH2OH) • Chemical properties • How to make it?
Bioethanol versus biodiesel • Feedstocks (competition with food industry) • Major producers • Process • Yields • Production facilities
Feedstock • Any starch/sugar rich biomass • Agricultural biomass • Corn • Wheat • Sugar cane • Sugar beets • Straws • Corn stover • Woody biomass
History • 1916 utilization of Clostridia acetobutylicum for acetone production by Chime Wizemann (fermentation process) • Smokeless gun powder • 1945 the second most important commercial fermentation process • 1960 growth of petroleum industry • Butanol production via petrochemical pathway • 1980-2008 • Biological pathway
Ethanol versus butanol • Energy efficiency • Butanol 96% of gasoline • Less volatile than ethanol • Less corrosive than ethanol • Water-tolerant alternate fuel • Less hydroscopic than ethanol (it doesn't pick up water) • pipeline • High viscosity • 2x ethanol • 5-10x gasoline • Problems in the fuel systems of butanol-fueled cars • Lower octane number compared to ethanol • Lower compression ratio and efficiency
Butanol-properties • Sweet smelling solvent • Industrial solvent • High melting point of 25.5°C causes it to gel and freeze near room temperature • Additive in gasoline • Industrial commodity • 370million gallon/year • $3.75/gallon • Petrochemical route
Production of butanol (1) • Fermentation • Weizmann organism (chemist Weizmann) • Anaerobic bacteria • Starch, sugars • Extracellular amylolytic enzymes • and amylase • Glucoamylase etc. • Distillation (boiling point) Clostridium acetobutylicum, the "Weizmann Organism"
ABE fermentation (2) • ABE fermentation (acetone, butanol, ethanol) butanol:acetone:ethanol (6:3:1) • Other by-products: • Acetic acid • Lactic acid • Propionic acids • Isopropanol • 1 bushel of corn: • 1.3 gallons of butanol • 0.65 gallons of acetone • 0.22 gallons of ethanol (each 1-2%)
Ethanol S. cerevisiae (yeast) Temp 30°C pH 6 No extracellular enzymes Monomeric sugars (6C) Products: 50% ethanol, 50% CO2 Toxicity of the final product over 100g/L of ethanol Butanol Clostridium (bacteria) Temp 30-40°C pH 6.8-7 drops to 5.0 (acidogenesis) and increases to 7.0 (solventogenesis) Presence of extracellular enzymes Starch, cellobiose and monomers (5 and 6C) Variety of products Toxicity of the final products 20g/L max of acetone, butanol, and ethanol Ethanol versus butanol fermentation (1)
Ethanol versus butanol fermentation (2) Ethanol S. cerevisiae Butanol Clostridium
ABE fermentation (3) • Pure sugar source • Toxicity of butanol to C.acetobutylicum • ethanol, thus butanol, higher recovery cost of butanol • Lignocellulosic substrate • More inhibitors generated during pretreatment • Lower butanol yields
Fermentation improvements • C.beijernickii • Hydrolysis, fermentation and recovery of butanol in 1 reactor • GM E.coli • Conversion of keto acids (components of a.a biosynthetic pathway) to butanol Acetoacetic acid
Environmental Energy Inc. • Environmental Energy Inc. • 2.5 gallons of butanol per corn bushel no acetone or ethanol • Other processes have not been able to achieve better than 1.3 to 1.9 gallons of butanol per bushel+A+E.
Cars running on butanol Over 10,000 miles around and across US